APUs are commonly used with large tractors or trucks (e.g., semi-tractors) to provide power to a sleeper cabin for the occupant (e.g., driver or passenger) to rest during a journey when the primary power source (e.g., tractor prime mover, high voltage battery source, etc.) is turned off (i.e., deactivated). This can reduce fuel consumption, maintenance costs, emissions, and noise generated by not requiring the tractor main power source to operate (e.g., idle when the main power source is a tractor prime mover) during occupant rest periods or other periods of vehicle non-movement.